Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F5/00—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
  • C23C14/34—Sputtering
  • C23C14/3407—Cathode assembly for sputtering apparatus, e.g. Target
  • C23C14/3414—Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C26/00—Coating not provided for in groups C23C2/00 - C23C24/00
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C24/00—Coating starting from inorganic powder
  • C23C24/08—Coating starting from inorganic powder by application of heat or pressure and heat
  • C23C24/10—Coating starting from inorganic powder by application of heat or pressure and heat with intermediate formation of a liquid phase in the layer

Definitions

• the present invention relates to fabrication and rejuvenation of refractory metal parts, and more particularly to fabrication and rejuvenation of refractory metal parts at net shape or near shape with controlled microstructure.
• the ingot is thermomechanically processed and further cold or hot worked as needed (or cold worked with intermediate annealing) to produce a desired shape, such as plate, sheet, rod or fabricated part (hemisphere, semi-hemisphere, conical, dished sheet, cup, box, etc.). Components may also be machined directly from ingots 3.
• the sintering process consumes a significant amount of furnace time, but it is required to provide sufficient mechanical strength in the bars and is a preliminary deoxidation step for the refractory metal powder, such as tantalum.
• the bars are usually electron beam-melted under a hard vacuum to remove chemical impurities.
• the electron beam melting process can also consume a significant amount of furnace time and power, such as three electron beam guns at 105 kilowatts for 8 to 16 hours. Remelting is usually required which also consumes significant furnace time and power, such as four electron beam guns at 150 kilowatts for 8 to 16 hours.
• Laser additive manufacturing is a direct deposition process that uses a high power laser and powder feeding system to produce complex three-dimensional components from metal powders.
• the high power laser and multi-axis positioning system work directly from a CAD file to build up the component using a suitable metal powder.
• This process is similar to conventional rapid prototyping techniques, such as stereolithography and selective laser sintering (SLS), and laser welding.
• Laser welding was developed to join two components or to fabricate an article integral to a component.
• a fully dense metal component can only be made with such additional steps as casting or HIP'ing (hot isostatic pressing).
• Such a laser process has been developed to manufacture near-net shape titanium components for the aerospace industry. But a process does not exist for still higher melting refractory metals, such as tantalum.
• sputtering targets of high temperature materials such as tantalum and other refractory metals (Ta, Nb, Ti, Mo, Zr, metals and alloys; hydrides, nitrides and other compounds thereof) used in integrated circuit manufacture and other electrical, magnetic and optical product manufacture usually are eroded in a non-uniform way during the process of sputtering which leads to a race track like trench on the operating side of the target.
• the targets In order to prevent any contamination of substrates or catastrophic break-through of coolant fluids behind the target, the targets generally are withdrawn from service well before the refractory sputter metal is penetrated, accepting the need for a new target after only a minor portion of the sputter metal has been consumed.
• the major part of the sputter target can be resold only at scrap price or recycled with difficulty and apart from this, the backing plate of the target needs to be removed and may be re-bonded to a new sputter metal plate for recycling. Consequently, there is a need to rejuvenate the refractory metal of the sputtering target to eliminate the need to recycle the whole target after only a minor share of the tantalum plate has been consumed.
• the invention relates to a process for making a refractory metal part comprising (a) loading powder metal particles into a hopper for feeding into a laser additive chamber, (b) loading a substrate into the laser additive chamber, (c) feeding the powder metal powders into the additive chamber onto successive points on the substrate in a linear trace, (d) melting the substrate and the powder with a laser beam and building up multiple coatings of a controlled microstructure, (e) tracing the substrate over a selected area with a combined deposition and melt beam and building up a coating of a controlled microstructure in multipe layers, and (f) building up a deposit from the coating and forming a refractory metal part.
• the invention also relates to a method for rejuvenating a tantalum sputtering target comprising subjecting an eroded region of a tantalum sputtering target to plasma deposition, forming a fully dense coating, and thereby rejuvenating the tantalum sputtering target.
• the invention also relates to a method for rejuvenating a tantalum sputtering target comprising subjecting an eroded region of a tantalum sputtering target to laser sintering, forming a fully dense coating, thereby rejuvenating the tantalum sputtering target.
• the invention also relates to a method for rejuvenating a tantalum sputtering target comprising subjecting an eroded region of a sputtering target to hot isostatic pressing, forming a fully dense coating, and filling the eroded region of a tantalum sputtering target, thereby rejuvenating the tantalum sputtering target.
• the invention can also include products made from such processes.
• the present invention is a process and the resultant product. The process is one to chemically refine and consolidate refractory metals and their alloys to a fabricated product of net shape or near-net shape with higher throughput, more consistency, and lower manufacturing costs compared to prior art routes.
• Powder metal is loaded into hoppers to be fed into the LAM equipment.
• a suitable substrate is loaded into a LAM chamber onto which the powder will be deposited and consolidated in a point-scan process.
• the laser is used to heat partially melt the substrate and partially or completely melt the powder.
• a fully dense deposit is built up that becomes the desired shape. This entire process is conducted in a chamber under inert conditions, such as argon, at, near or below atmospheric pressures but can also be conducted under a hard vacuum.
• the relatively high heat or power input to the powder particles and the short diffusion distance results in purification of the powder and the resultant product.
• the process yields are 90 percent or more, requiring minimal machining to clean up deposit edges and product surfaces depending on final shape and end use application.
• the process will yield the necessary grain purity and have a columnar grain structure to aid uniform sputtering characteristics.
• the race track trench on the face of the deteriorated tantalum sputtering target is filled by laser sintering, plasma deposition or HIP-bonding powder/plate material which will yield a fully dense coating.
• laser sintering or plasma deposition the target could be rejuvenated without debonding the backing plate from the target.
• HIP-bonding either low oxygen Ta powder or any Ta plate material could be used. Rejuvenation is an economic process if filling the trench by any of the proposed methods is cheaper than recycling the whole target. No debonding of the backing plate is needed. It can be reused as many times as desired.
• Used sputtering targets can be processed to fill the race track trench or other erosion zone on the face of the target by a placement or deposition of sputter metal and sinter bonding by laser or EB heating for sintering, plasma discharge coupled with deposition or HIP-bonding powder/plate material.
• Use of these methods will yield a fully dense coating. This avoids the need for decoupling the tantalum from the copper, filling the erosion zone of the tantalum plate with tantalum powder and HIP bonding and reassembly.
• laser or EB scan sintering or plasma discharge coupled with deposition the target can be rejuvenated without separating the backing plate from the target.
• the various forms of rejuvenation produce a filled erosion zone with microstructure similar to the balance of the target.
• the rejuvenation of a refractory metal (e.g. tantalum) target eliminates the need to recycle the whole target after only a minor share of the sputter plate has been consumed. Such rejuvenation can be more economical than recycling the whole target. No separation of the bonded backing plate (e.g. copper) is needed.
• Fig. 1 shows the five deposits (products) formed from the preferred embodiments of the process of the invention
• Fig. 2 shows a typical metallographic section taken from each such deposit
• An embodiment of the present invention is a laser process to produce high purity refractory metal and alloys formed from refractory metal powder.
• the tantalum powder (-120+325 mesh), and a tantalum plate substrate applied in a depositing apparatus as described in U.S. 6,269,536, incorporated herein by reference in its entirety).
• the laser energy was approximately 17 kW delivered.
• Figure 1 shows the five deposits formed from the laser process. Each deposit is the result of approximately five to seven layers with each layer being approximately 0.010" thick.
• the physical property differences described above also meant the deposition rates had to be much lower than for titanium.
• the higher melt temperature and thermal conductivity of tantalum compared to titanium meant the tantalum molten pool was probably smaller and a smaller quantity of powder could be melted by the available laser power.
• Table 1 shows the results of the chemical analysis (GDMS) of the starting powder and the final deposits.
• GDMS chemical analysis
• Nb, and W refractory metal content
• titanium and vanadium there was a measurable reduction in the metallic contamination of the deposit. Titanium and vanadium contamination came from previous work in the test equipment conducted with Ti-6AI-4V alloy.
• Figure 2 shows a typical metallographic section taken from each deposit. No porosity was found in any of the sections examined except at the very outer surface of the deposit. The deposits examined had from two to five grains (grain boundaries are marked with arrows) across their width.
• Tables II and III show the mechanical test results.
• the Vicker's Hardness Numbers (VHN, 500g) for three of the samples are slightly higher than might be expected for rolled and annealed tantalum sheet (VHN of approximately 100). These deposits have not been annealed and the VHN suggests the material is not brittle.
• the slightly higher hardness of sample 1 as compared to samples 2 and 3 is the result of its slightly higher oxygen content.
• Table III shows the room temperature yield and ultimate strengths of these three deposits meet the ASTM specifications for rolled and annealed tantalum sheet.
• Figs. 3-4 show a tantalum (Ta) sputter plate bonded to a copper (Cu) backing plate which may include additional complexity such as bonded-on water cooling coils (CL) or even be part of a large cooling liquid reservoir and/or have complex flanges and mechanical and electrical attaching structures.
• Ta tantalum
• Cu copper
• E indicates a typical race track form erosion zone arising from sputtering usage.
• a 15-20 KW (preferably 20-25 laser beam LB formed by a case C and conventional scan optics Ml, M2 which can be wholly in the chamber or, partly outside the chamber using a window for beam passage can be traced in raster scan fashion over the erosion zone, as the powder falls, to melt powder particle surfaces and enable particle to particle bonding and bonding to the base of the erosion zone continuously and repeatedly around the zone until it is filled.
• Powder mass calculations and/or optical monitors can be used to determine completion and a cut-off of filling.
• the laser can provide post-fill heating to complete the sintering.
• Separate target heaters can be used to preheat the target or provide additional heat during the rejuvenation.
• the invention can also be applied to other refractory powder metals, such as Re, W, Mo, W alloy, Mo, alloy, RE alloy, niobium, tantalum alloys, and niobium alloys.
• refractory powder metals such as Re, W, Mo, W alloy, Mo, alloy, RE alloy, niobium, tantalum alloys, and niobium alloys.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Manufacturing & Machinery (AREA)
• Powder Metallurgy (AREA)
• Physical Vapour Deposition (AREA)
• Other Surface Treatments For Metallic Materials (AREA)
• Coating By Spraying Or Casting (AREA)

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• 2003
  • 2003-01-22 EP EP10173686A patent/EP2278045A1/en not_active Withdrawn
  • 2003-01-22 JP JP2003562354A patent/JP2005516117A/ja active Pending
  • 2003-01-22 BR BR0307105-7A patent/BR0307105A/pt not_active IP Right Cessation
  • 2003-01-22 RS YU65004A patent/RS65004A/sr unknown
  • 2003-01-22 KR KR10-2004-7011395A patent/KR20040103920A/ko not_active Application Discontinuation
  • 2003-01-22 NZ NZ534237A patent/NZ534237A/en unknown
  • 2003-01-22 CA CA002473830A patent/CA2473830A1/en not_active Abandoned
  • 2003-01-22 EP EP20030731631 patent/EP1470265A2/en not_active Ceased
  • 2003-01-22 IL IL16283703A patent/IL162837A0/xx unknown
  • 2003-01-22 RU RU2004125882/02A patent/RU2333086C2/ru not_active IP Right Cessation
  • 2003-01-22 WO PCT/US2003/001825 patent/WO2003062491A2/en active IP Right Grant
  • 2003-01-22 PL PL03370455A patent/PL370455A1/xx not_active Application Discontinuation
  • 2003-01-22 MX MXPA04007103A patent/MXPA04007103A/es active IP Right Grant
  • 2003-01-22 US US10/501,837 patent/US7651658B2/en active Active
  • 2003-01-23 TW TW092101421A patent/TWI314591B/zh active
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• 2004
  • 2004-07-20 ZA ZA200405765A patent/ZA200405765B/en unknown
  • 2004-08-20 NO NO20043487A patent/NO20043487L/no not_active Application Discontinuation

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